import os
from flask import Flask


def create_app(test_config=None):

    app = Flask(__name__, instance_relative_config=True)
    app.config.from_mapping(
        SECRET_KEY="dev",
        DATABASE=os.path.join(app.instance_path, 'njlfc.sqlite'),
    )

    if test_config is None:
        app.config.from_pyfile('config.py', silent=True)
    else:
        app.config.from_mapping(test_config)

    try:
        os.makedirs(app.instance_path)
    except OSError:
        pass

    '''
    注册蓝图
    '''
    from . import nav
    app.register_blueprint(nav.bp)

    # 用于测试
    @app.route('/hello')
    def hello():
        return 'Hello!'

    return app
